The present invention relates to an apparatus and a method for measuring the content volume of a container.
One conventional method for accurately measuring the content volume of a container is to measure the quantity of a liquid, in particular water, which is poured into the container until it is filled up. When this method is employed in a container manufacturing process, it is necessary to measure a large number of containers one after another, pour out the water therefrom and dry them after the measurement. This calls for a drainage or recovery installation for the water used and an installation for drying the measured containers. Further, the drainage and recovery installations must be kept leak-free. Thus the volume measurement using water requires bulky arrangements and consumes much time. Besides, to handle water is troublesome in various aspects.
In a similar volume measurement using a gas in place of water, since the gas is compressible, the measurement is affected by the gas pressure and is readily susceptible to temperature. In addition, since gas is lower in viscosity than water, its leaks in the container itself and the coupling portion between the container and the measuring apparatus have a great influence on the measurement. Accordingly, high precision measurements are difficult in the prior art.